VALDEZ AND SHOUP GLACIERS 245 pied by the Camicia Glacierl which is detached from the main ice tongue, as already stated. Between this former tributary and the Valdez Glacier is a triangular depression into which the Valdez Glacier bulges slightly (Fig. 22) and this depression, one or two hundred feet deep, sometimes contains a marginal lake, like the Merjelen See on the border of the Aletsch Glacier in Switzerland. At the time of our visit in August, 1909, there was no lake present, but the numerous stranded icebergs attested its recent presence, the fact that these icebergs had not melted and that some of them rested upon last winter's snowbanks showing that the lake had existed in the spring of 1909. The lake \ les FIG. 28. TRIANGULATION ON FRONT 07 VALDEIZ GLACIEIE IN 1909. For location of stations A and B see Fig. 22. occupied a triangular area of nearly half a square mile and probably received part of its water from a stream issuing from Camicia Glacier and part from the marginal drainage of Valdez Glacier itself. The lake possibly forms every spring or winter, when glacial advance and freezing closes crevasses and sub-glacial channels, and drains again early in the summer through a submarginal channel. That the draining of the lake of 1909 had been completed in August is shown by the icebergs (PI. XCVI) in the picture reproduced here. This detached tributary, which is three-eighths of a mile wide and has one south i Named for the late L. S. Camicia of Valdez, whose valuable observations on Valdez Glacier have already been mentioned.